Improvement in furnaces and steam-generators for heating



ZS-heets--Sheettl B. R. HAWLEY. Furnaces and Steam Generators for Heating, &c.

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2 Sheetsj-Sheet 2.' B'. R. HAWLEY.

Furnaces and Steam Generators for Heating,- Gru.

No. 136,510, PatemedMarch4,187s.

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BENJAMIN a. HAWLEY, on NORMAL, ILLINOIS.

IMPRVEMENT IN FURNACES AND STEAM-GENERATORS FR HEATING. &c.

Specification forming part of Letters Patent No. l36,5 H0, dated March 4, 1873.

To all whom it may concern:

Be it known that I, BENJ. R. HAWLEY, of Normal, McLean county and State of Illinois, have invented certain new and useful Improvements in Furnaces and Steam-Generators for H eating by Steam or Hot Air, of which the following is a specification:

The essential feature of this invention consists of a mode of applying heat in furnaces or steam-generators for heating by steam or hot air on the principle or plan known as bottom or base exhaustion in the ventilation of buildings, or as in the burning of brick in modern close kilns, where the air or gases find their exit at the bottom of the room or chamber by or through a vertical shaft or chimney. By this plan I avoid all smoke-lines in the heater or boiler, either diving or horizontal, and secure a large combustion-chamber which will never clog or require cleaning out; and also produce the most perfect combustion ofthe fuel, and prevent the extinguishing of the flame, which is the result in all tubular heaters and boilers where the gaseous products, combustible and incombustible, are forced into too close proximity in entering the ilues. No longcontinued flame can be sustained or is ever seen in small flues, while in large ones it is often perfectly sustained and carried a distance of twenty or thirty feet. Also, by this plan I secure the separation ot' the gases, the lighter and combustible ones naturally rising to the top of the chamber, and the heavier, as carbonio-acid gas,falling to the bottom and escaping. This gives me the advantage of longcontinued flame and greater heat, which spreads out in a stratum in all directions to the walls of the chamber conning it, causing it to pass from above downward in order to nd exit, so enabling me to hold and utilize all the heat discharged into the chamber, and producing equal and uniform temperature on all heating-surfaces on the same level. It also acts on the plates and tubes conducting the heat to the air or water to be heated more directly in the lines by which it is conducted through them than can be secured by the ordinary arrangements.

The apparatus used may be tubular or oth-v erwise, without or with vertical tubes, in which theheat from the furnace ascends to the crownsheet, and spreading out in all directions between and around the tubes, instead of through them, as is usual, lling the whole chamber, and descending in like manner gradually t0 the bottom, and escapes at or near the bottom by a vertical iiue or shaft, either on the outside or within the heater or boiler, as shown by dotted lines in Sheet 1 of the drawing.

By this plan the heat is arrested in its direct upward liow from the furnace by the crownsheet, and is thereby caused to turn and impinge directly against the plates, so that, instead of moving rapidly in currents parallel with them and escaping in such manner as to have the least effect, it is caused to act more nearly at right angles to them, thereby effecting the best results, for they absorb it best in this way, and conduct it more rapidly through to the air or water. Advantage is thus taken of the well-known tendency of hot air and gases to spread laterally in all directions when checked in their natural upward movement, effecting direct action on the plates, causing theheat to escape slowly, so increasing the duration of its action with comparative short tubes much longer than with long tubes or plates, when it escapes through horizontal or vertical lines in the ordinary way. Also, by this plan the greatest heat is concentrated in the upper portion of the heater or boiler around the tubes and other heating-plates, and under the crown-sheet, where it gives the best results, while the gases pass as they become reduced in heat to the lower portion of the heater or boiler, where the air or water is coldest, so that, however great the radiation of the heat may be, it acts advantageously as long as it is greater than the temperature of the air or water supplied, thus making it possible to utilize all the heat.

By the use of the conical tubes I provide for the expansion of the air or water and the free circulation, so that all parts of the plates are constantly supplied, and are not liable to be burned, as is often the case, particularly in boilers, even when they are under water. The steam being formed faster than the water can be supplied, it lifts the water oft' the plate, and leaves only steam next to the iron, and so is soon superheated and the plate burned.l By my plan of conical, tubes, the largest amount of water or air is always where the largest amount of heat will meet it, and the crownsheet is so out up or reduced by the largeend of the tubes that but small parts are subject to the heat and cannot burn.

Figure 1, Sheet 1, is a sectional elevation of a tubular boiler constructed according to my invention, the section being taken on the line .fr a: of Fig. 2, Sheet 2. Fig. 2, Sheet 2, is a horizontal section taken on the liney y otl Fig. 1, the small circles showing the size of the bottom of the tubes, and the dotted lines the size of the top of the same.

In Sheet 1, Fig. 1, A represents a vertical shell of a boiler surrounding` an annular water-space, C, and inclosing a steam and Water space, C', by its dome W. G represents the crown-sheet separating the heating-chamber K from the space C. D represents conical tubes extending through the heating-chamber K, and connecting water-space C at top and bottom. E is a furnace or fire-box, the Whole top of which is open, arranged in the heatingchamber K, with suitable openings M and N through the shell A and Water-space U, for supplying the fuel and removing ashes; also for admitting air to supply or support combustion. From the fire-box E the heat rises directly to the crown-sheet G, and then first spreads laterally in all directions, heating all surfaces alike on the same level, and coming in contact with all sides ot' the tubes; also with the inner Walls B of the annular space C and impinging thereon in lines at right angles to them, attacking them with greater intensity than When moving parallel with them, as in boilers or heaters of ordinary construction. The heat is therefore not only conducted directly through the plates and tubes in greater measure than it otherwise would be, but their surfaces operate like the conductingpins sometimes used in boiler-flues to conduct the heat through the plates, being arranged to project at right angles from the surface into the interior space across the current for being heated thereby. In this case, the tubes D and the plates B being heated in a similar manner, they conduct the heat in a greater measure from the chamber K through to the water or air. From the upper part ot the heating-chamber K the heat gradually descends in a stratum over the Whole surface of the chamber around and between the tubes D, and finally escapes through the central passage F and horizontal passage T into a vertical fiue, V; or it may be by vertical shaft passing down through the crown-sheets W and G, and stopping near the bottom otl chamber K, as indicated by dotted lines o o, Fig. 1. The area of the heatingchamber K will be very much larger in crosssection than that ofthe iiue or escape passage F, so that while the movement ot the gases in the escape-passage Will be sufficiently active to make the draft strong the descending motion of the heat in the chamber K Will be slow, affording ample time' for the heat to be mostly absorbed by the time the currents escape at the bottom.

suitable dampers will be provided to govern the action in this respect, so that incase it is desired to economize fuel to the greatest extent that it may be the descendingcurrents may be sufficiently checked or retarded for that purpose; but, in case the more rapid generation of steam is required, with less regard for economy of fuel, the escape-passage may be made larger, and thereby a more rapid descent of the heat effected.

It will 'be observed that by this plan very large heating-space may be employed, With a very small furnace or grat-e surface, Without incurring the difficulty attendingthe same conditions in boilers or heaters with horizontal or vertical escapes, namely, the impossibility of heating the whole of the surface above or beyond the furnace uniformly, which in such boilers cannot be done without an excess of heat, because it escapes so rapidly through the direct passages that those parts not in the direct course will not receive their due proportion, whereas in this case, by reason of the escape being at the bottom, the heat on arriving at the top of the heatin g-ch amber spreads through all the space by its natural tendency to find the most direct upward escape, and of necessity heats all parts alike. This provides ample space for the combustion of the gases Without danger of any part failing to be heated, so that the requisite quantity of air for consuming the gases rising from the coal below may be admitted to the space above to insure perfect combustion. Moreover, the noncombustible carbonio-acid gas, which is heavier than the combustible gases, is permitted to descend at once from the entrance into the burnin g-chamber K to the escape-passage below, and leave the combustible gases to be consumed unobstructedly, so that by the introduction of a suicient quantity of `oxygen to the chamber K above the furnace, or into the furnace above the coal, the combustion will be so perfect that smoke will not be generated to any considerable extent.

I propose in practice to make the tubes D largest at the top and tapering to the bottom, so as to have a. greater amount of heatingsurface in the upper portion of the boiler, where the gases will be the hottest and most effective, and so that the surface will diminish with the cooling of the gases as they descend and become less effective, thereby graduating the heating-surface to the capacity ot' the heat.

The operation of this apparatus for heating purposes by means of air will be precisely the same as for generating steam, air being substituted for water.

It will be observed that the construction of both boiler or heater will be of the simplest and most inexpensive kind.

It will of course be understood that either boiler or heater may be built without any tubes, they not effecting the working of the principle of bottom exhaustion, but only being added to increase the heating-surface, and I reserve to myself the right to use them or not, as circumstances shall indicate; but

I claim as my invention- 2. rl`he arrangement of the shell B, furnace 1. A boiler or heater in which a fire-box is E, tubes D, and vcrown-sheet G, Water-space so arranged that the products of combustion C, and escape-passage F T V, substantially as are discharged into the entire chamber, rising represented in Sheet l of thedrawing. to the crown-sheet and spreading out to the Y B. R. HAWLEY. Walls, and descending in a stratum over the whole chamber to the bottom and escaping Witnesses:

thereat, substantially in the manner herein MARY A. HAWLEY, described. KATE HAWLEY. 

